Active Site

Ribonuclease A, active site (IPR023411)

Short name: RNaseA_AS

Description

Pancreatic ribonucleases (RNaseA) are pyrimidine-specific endonucleases found in high quantity in the pancreas of certain mammals and of some reptiles [PMID: 3940901]. Specifically, the enzymes are involved in endonucleolytic cleavage of 3'-phosphomononucleotides and 3'-phosphooligonucleotides ending in C-P or U-P with 2',3'-cyclic phosphate intermediates. Ribonuclease can unwind the DNA helix by complexing with single-stranded DNA; the complex arises by an extended multi-site cation-anion interaction between lysine and arginine residues of the enzyme and phosphate groups of the nucleotides. Other proteins belonging to the pancreatic RNAse family include: bovine seminal vesicle and brain ribonucleases; kidney non-secretory ribonucleases [PMID: 2734298]; liver-type ribonucleases [PMID: 2611266]; angiogenin, which induces vascularisation of normal and malignant tissues; eosinophil cationic protein [PMID: 2473157], a cytotoxin and helminthotoxin with ribonuclease activity; and frog liver ribonuclease and frog sialic acid-binding lectin. The sequence of pancreatic RNases contains four conserved disulphide bonds and three amino acid residues involved in the catalytic activity.

Pancreatic ribonucleases (EC:3.1.27.5) are pyrimidine-specific endonucleases present in high quantity in the pancreas of a number of mammalian taxa and of a few reptiles [PMID: 3074337, PMID: 3940901]. As shown in the following schematic representation of the sequence of pancreatic RNases there are four conserved disulphide bonds and three amino acid residues involved in the catalytic activity.

                        +---------------------------+
                        |        +------------------|------+
                        |        |                  |      |
     xxxxx#xxxxxxCxxxxxxC#xxxxxxxCxxCxxxCxxxxxCxxxxxCxxxxxxCxxx#xxx
                 |      ****        |   |     |
                 |                  +---+     |
                 +----------------------------+

'C': conserved cysteine involved in a disulphide bond.
'#': active site residue.
'*': position of the pattern.

A number of other proteins belongs to the pancreatic RNAse family and these are listed below.

  • Bovine seminal vesicle and bovine brain ribonucleases.
  • The kidney non-secretory ribonucleases (also known as eosinophil-derived neurotoxin (EDN) [PMID: 2734298]).
  • Liver-type ribonucleases [PMID: 2611266].
  • Angiogenin, which induces vascularization of normal and malignant tissues. It abolishes protein synthesis by specifically hydrolyzing cellular tRNAs.
  • Eosinophil cationic protein (ECP) [PMID: 2473157], a cytotoxin and helminthotoxin with ribonuclease activity.
  • Frog liver ribonuclease and frog sialic acid-binding lectin [PMID: 2710786].

The signature pattern for these proteins includes five conserved residues: a cysteine involved in a disulphide bond, a lysine involved in the catalytic activity and three other residues important for substrate binding.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns